The long-overdue annual U.S. Defense Department report on China's military says the country continues to build longer-range capabilities designed to extend the reach of its power to influence regional disputes, to expand its territorial waters beyond international norms and to deny adversaries the use of sea lanes and airspace as well as outer space and cyberspace.

The report, required by the Congress, says China is developing a long-range anti-ship missile and is preparing to field aircraft carriers later this decade as part of its effort to become the preeminent military power in Asia. That is a position the United States now holds, and officials say intends to maintain.

The report says China is also building more and more sophisticated submarines, surface ships and missiles of various ranges, and is developing its capabilities to conduct "information warfare."

Speaking about the report on condition of anonymity, a senior defense official said China is working to narrow the gap between its aspirations and its capabilities.

According to the document, those aspirations include exclusive access to natural resources far from Chinese shores in the South China Sea and the ability to influence the outcome of regional disputes in its favor, particularly regarding the future of Taiwan.

A Pentagon official said China's long-term participation in international anti-piracy efforts off the coast of Africa demonstrates its ability to sustain a force far from its home waters. Last year's report said it would be 2020 before China could do that in a substantial way.

The only on-the-record Pentagon comment on the report came from spokesman Bryan Whitman.

"This is a report in which we very carefully choose the language that's in the report, as you know. We tend to think the report stands on its own. We don't get in the business of trying to overly explain the report or anything of that nature."

The report estimates that China spent about $150 billion on defense last year -- nearly double its officially announced budget. By either the official or U.S. figures, China's defense spending has at least quadrupled since 1996. The United States spends more than $500 billion annually on defense.

The Pentagon official who spoke on condition of anonymity again urged China to resume military contacts with the United States, which it suspended after the latest U.S. arms sale to Taiwan in January. The official said the continuing expansion of China's military capabilities makes such contacts particularly important in avoiding misunderstandings and miscalculations that could lead to conflict.

The official said the report was nearly half a year late due to issues he would not specify that came up as it made its way through clearances in the Pentagon and at several other U.S. government agencies.